Adaptive drain algorithm for clothes washers

ABSTRACT

This disclosure is related to a system and method which minimizes the period of time in which a drain pump is running in a washing machine unit. The method includes determining the amount of washer fluid used to fill a washing machine tub when the washing machine has entered the draining portion of the cycle, measuring the time it takes in order to trip a water level sensor. The method generally continues with calculating a predicted time to drain and operating a drain pump according to the predicted time to drain. Use of this method minimizes the opportunities for machine malfunctions while further minimizing the opportunity for the pump to run dry, creating noise and increasing the length of the entire washing cycle.

BACKGROUND

This disclosure relates to a method and apparatus for an adaptive drain. More particularly, this disclosure is directed towards a method and apparatus for minimizing the period of time in which a drain pump is running in a washing machine by use of an adaptive drain that can establish a predicted time to drain so that a washing machine cavity or tub may be drained during a portion of time within the washing cycle. However, this application should not be limited to that particular application and may find application benefit in related environments and uses. For example, this disclosure may have application in regulating the time it takes to drain other appliances.

A need exists for a product that provides a means to predict the time in which a washer tub will become empty during the draining portion of the washing cycle. Currently in the art, washer machines generally have a default time in which a drain pump operates. Historically, this default time would be a time between when a drain pump is initiated and the unit proceeds to the next cycle. While this works in many cases, it has the disadvantage of a pump running for that full time period when it is not necessary. This situation unnecessarily generates noise, especially when the washer tub has already emptied and can lead to customer dissatisfaction. In other situations, the tub may not have fully emptied within the set period of time. This may be the result of restrictive drain situations (e.g. elevated drainage systems) or when there are large loads put into the washer and may create machine malfunctions upon progressing to the next washer cycle, for example, the spin cycle.

Some newer washers have electronic controls which monitor the pump current draw. When the wash tub empties and the pump runs dry, the pump current draw correspondingly decreases. The control senses this decrease in current draw and can hence take appropriate action, such as shut off the drain pump. While this system works well, it adds a significant cost to the washing machine through adding current sensing hardware to the electronic control.

Therefore, there is a need in the industry to provide a method and system for predicting when a tub will empty given different variable factors. These factors may include load size and drain system restrictions. Furthermore, there exists a need in the industry for this system not to add significant cost to the washer machine. This disclosure solves the aforementioned problems and others.

SUMMARY OF THE DISCLOSURE

A method for minimizing the period of time in which a drain pump is running in a vertical load washing machine is disclosed.

An exemplary method includes determining an amount of fluid to fill a washer machine tub; measuring a time to reach a first level and a second level in the washing machine tub during draining; calculating a predicted time to drain the wash tub based, at least in part, on the time to reach a predetermined level in the wash tub during drain and the initial amount of fill, and operating a drain pump for a period of time related to the predicted time to drain.

An exemplary method may also include that the first and second levels are pressure switches that may contain fault detection mechanisms.

An exemplary embodiment of a method of operating an adaptive drain includes determining a measure of fluid in a washer tub; initiating a timer; initiating a drain pump; recording a time to reach a predetermined level in the wash tub, and calculating a predicted time to drain based at least in part on the time to reach a predetermined level in the wash tub and the measure of fill in the washer tub.

An exemplary embodiment may also include a system for an adaptive drain that calculates a predicted time for a washing machine to drain out fluid comprising a washer tub having an upper level switch and a lower level switch; a drain pump configured to pump an amount of fluid out of the washer tub, and a controller adapted to regulate the drain pump in order to drain the washer tub for a period of time that is calculated to reflect a relationship between the time between initiation of the drain pump and the time to reach a predetermined lower level and the amount of fluid in the tub.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the environment in which the adaptive drain system is configured to operate including a washer tub and a drain pump;

FIG. 2 shows the washer tub of FIG. 1 with fluid filled to a first level or amount;

FIG. 3 shows the washer tub of FIG. 1 and FIG. 2 with fluid filled to a second level;

FIG. 4 shows a flow diagram outlining the method according to one embodiment of the disclosure;

FIG. 5 a shows a flow diagram outlining a method according to another embodiment of the disclosure.

FIG. 5 b shows the continuation of FIG. 5 a.

DETAILED DESCRIPTION OF THE DISCLOSURE

This disclosure relates to software program that provides a means to predict the time when a washer tub will become empty during the draining portion of a cycle without adding product cost. In one embodiment of this disclosure, the washing machine includes of a tub for holding wash water and at least one water level detection sensor which is used to detect the water level. Upon the washing machine filling with water, a controller records the amount of water being dispensed into the tub. After the unit fills, the agitation portion of the cycle is completed. The unit then proceeds to the draining portion of the cycle. A timer is initiated when the drain pump begins draining the water from the tub. The level detection sensor monitors the time at which the water reaches a predetermined level. This information is recorded and a controller tabulates the empirical data and performs a calculation in order to predict a time period upon which the tub will be emptied. The pump then proceeds to pump that duration of calculated time.

Shown in FIG. 1 is a representation of some of the relevant elements of a washing machine. As shown, FIG. 1 includes a washer tub 102 including an upper level sensor 104 and a lower level sensor 106. Inside of the washer tub 102 is an agitation device 108 which may be an agitator, a pulsator, an impeller, a wash plate, or any other comparable device used to impart mechanical action to the wash load. Adjacent to the washer tub is a fill pipe 112 and a drain pump 114. This is but one embodiment of the system into which the claimed disclosure may be implemented. A variety of other systems exists and will still fit within the scope and spirit of the present disclosure.

The washer tub 102 may be filled by the fluid passing (or flowing) through the fill pipe 112. The fill pipe 112 is configured to dispense washer fluid, e.g., water into the washer tub 102, in order to wash clothes. The amount of fluid introduced into the tub can be determined by a flow rate valve 116. The flow rate valve 116 is adjacent to the fill pipe 112 and is generally adapted to measure the amount of fluid that passes through the fill pipe 112 and into the washer tub 102. A controller 118 records the amount of water dispensed into the tub 102. This may be accomplished through multiple means, although one common implementation includes using a timed fill with the regulated flow rate.

After the unit fills with wash water, the washer proceeds to the washing portion of the cycle. This portion is well known in the art and may include an agitation cycle where the agitation device 108, moves the clothes that need to be washed.

Once the washing portion of the cycle is complete the unit proceeds to the draining portion of the cycle. At this portion, the drain pump 114 is actuated and the fluid begins to be removed from the washer tub 102. The controller 118, through a process described in further detail below, dictates how long the drain pump 114 operates. This time period is preferably the minimal amount of time required for the fluid to be removed from the tub 102. This calculation takes into account the amount to fill the tub 102 which was previously recorded and the time for the water level to reach at least the lower level sensor 106.

FIG. 2 shows the system of FIG. 1 with water 120 filled up to the upper level sensor 104. One level of water while the washing machine unit is engaged in the washing portion of the cycle is illustrated. It should, however, be noted that this is but one embodiment of the disclosure. The washing machine tub is filled with water up to or above the upper level sensor. In another embodiment, the water does not fill to an upper level sensor. In yet another embodiment, there is no upper level sensor in which to measure the level of water. It should also be noted that these levels and proportions illustrated in the figures are not necessarily shown to scale and the sensors may be spaced in different positions relative to the washer tub 102.

FIG. 3 shows the water level 122 after the tub has been drained to the height of the lower level sensor 106. At this point a time to trip (TTT) may be measured by calculating the time from the initiation of the drain pump 114 until the water level has reached the lower level sensor 106 as shown as the difference in water height level when comparing FIG. 2 to FIG. 3. A first level could be used while not including an upper level sensor 104. For example, in this embodiment the time to trip may equal the time between when the drain pump 114 was initiated until the time the water level 122 reached the lower level sensor 106. In any event, the controller 118 may use the time to trip value and amount to fill value in order to calculate a predicted time to drain (PTTD) value. In this manner the controller 118 regulates the amount of time in which the drain pump 114 will operate in relation to the predicted time to drain. This value is useful in calculating a minimum time that the drain pump should run that will still ensure that all of the fluid will be drained from the washer tub 102.

Now referring to FIG. 4, a flow chart showing some of the steps for one embodiment of the disclosure is shown. The method begins with determining the fill amount (at step 402). In one embodiment, the fill amount through the fill pipe 112 is calculated by measuring the consistent flow rate as regulated by the flow valve 116 as multiplied by the time the valve is open. This step may be recorded by a controller 118 as the washing fluid fills the tub 102.

The method continues with actuating or operating the drain pump (at step 404). This step allows the washing fluid to be drained from the tub 102. As the pump 114 drains the tub 102, the fluid will generally pass through at least two significant points. The first point relates to a first pressure switch 104 (or, in the alternative, at the level of water fluid at the initiation of the drain pump 114 operation) and the second point relates to the level of the lower level switch 106.

The method continues (at step 406) with recording the time to trip. The time to trip is generally calculated by measuring the time between two significant points of the previous step. This time may vary depending on the implementation of the method. For example, the time may be very short if the two points in which this calculation is measured are very close together. This time may also depend on the amount and absorbency of the items which are currently in the washer tub 102.

The method continues with calculating a predicted time to drain (at step 408). The predicted time to drain may be calculated using the fill amount and the time to trip number. The formula in which the predicted time to drain is calculated may vary depending on the washer unit. However, this predicted time to drain should be a relatively accurate time measurement determining when the drain pump 114 has removed a sufficient amount of water out of the tub 102.

The method continues (at step 410) with operating the drain pump according to the calculated predicted time to drain. Once the predicted time to drain is known, the controller 118 uses this information to operate the pump for the minimum amount of time required in order to drain a sufficient amount of fluid out of the tub 102. This may be useful in both ensuring that the tub 102 is fully drained and preventing the pump from running dry. When the pump runs dry, generally it creates noise and lengthens the time for the washer cycle. Furthermore, it creates situations where customers may call a service technician in order to repair the washing machine unit, even though pump operability is not an issue.

Now referring to FIG. 5 a and FIG. 5 b, a more detailed embodiment of the method disclosed in FIG. 4 is shown. The method begins (at step 502) with initiating the fill. This step may be implemented through actuating the fill valve in order to fill the washing machine tub 102 through the fill pipe 112. Generally (at step 504), the number of Gallons To Fill (GTF) may be determined. This may be done through a flow regulated valve 116 which can regulate the flow to a rate which may easily be calculated.

The method continues (at step 506) with completing the fill and beginning agitation. The method continues on (at step 508) with agitation. In these two steps, the agitation device 108 is used in order to wash the clothes. The method continues until (step 510) when agitation is completed.

The method continues (at step 512) with setting the timer to zero and then starting the timer. The timer is useful in calculating the time to trip. Therefore, it is initiated right before step 514 of turning on or operating the drain pump. Once the drain pump operation is initiated, the fluid will begin to drain from the tub 102 and this time is useful in calculating how long it takes the water level to reach the lower level switch 106. The time is measured, as shown in this preferred embodiment, from the time that the drain pump is initiated, or alternatively the time may be measured at some other point, such as when the upper level switch 114 is open. In any event, a time to trip is calculated based at least in part on the timer.

The method continues with determining if the upper level switch is open (at step 516). In this embodiment, the switch is open when water has cleared from the switch. Stated another way, the switch will be open when there is no water at the level of the switch 104. If the switch is not open, the next step in the process (at step 518) is determining if the lower level switch is open. If neither switch is open, the cycle is repeated until one of the switches opens. If the lower level switch is open, the upper level switch should also be open. Otherwise, the method continues on (at step 520).

The method continues (at step 520) with turning off the drain pump. The drain pump will need to be turned off in this case because there is a hardware error. Therefore, when the situation occurs when the lower switch opens before the upper switch, a switch fault is registered. When the lower level switch opens while the upper level switch is not open, a signal is provided to the controller 118 that there is fluid e.g. water at the upper level switch 104 while there is no fluid at the lower level switch 106. Since this situation is seemingly not possible under intended operation, a presumption is then made that there is a mechanical issue with the upper level switch 104.

If at step 516 it is determined that the upper level switch is open, at step 524, then represents the process of determining if the lower level switch is open. In this embodiment, if the lower level switch is not open, continued verifications are undertaken checking and running the timer for 6 minutes (360 seconds). Of course it will be understood by one skilled in the art that “6 minutes” is merely representative of a time period and that other time periods may be used without departing from the features of the present disclosure. At step 526, there is a determination as to whether the time has exceeded the additional time period, i.e., the 6 minute threshold.

If the 6 minute threshold has not been exceeded, the method continues with testing of the lower level switch to determine whether it has been open continuously or the 6 minute threshold has passed. If the 6 minute threshold has been exceeded, next step in the process continues (at step 528) by turning off the drain pump. Once the timer has surpassed the lower level switch time threshold, if the switch has not opened, the drain pump is shut off. This action is taken because after the threshold has been exceeded, either the fluid has drained out of the wash tub 102 and the lower level switch 106 has errored (exhibits a fault), or the pump 114 is not draining fluid out of the washer tub 102. In either condition, the method continues on (to step 530). At step 530, the control registers a lower switch fault and the method comes to an end.

If the upper level switch 104 is open and the lower level switch 106 is also opened, then the process is continued (at step 532) with recording the time. This recorded time value becomes the time to trip (TTT) and is used (at step 534) in order to determine the predicted time to drain.

The predicted time to drain (PTTD) may be calculated through a variety of methods. In a preferred embodiment, the calculation includes 59.4+20+1.64 TTD−3.62 GTF. However, this is but one embodiment and the predicted time to drain may be calculated through a variety of means. However, generally the predicted time to drain will take into account the time to trip and the amount of fluid required to fill the washer tub 102 for this wash. The constants of the equation may be unique for each washer configuration.

The method continues (at step 536) with determining if the predicted time to drain is greater than a minimum drain time. In this embodiment, the minimum drain time is equal to 165 seconds. However, the minimum drain time may vary and still fall within the scope of the disclosure.

If the predicted time to drain is greater than the minimum drain time, e.g., 165 seconds, then the method continues at step 538 by adding 15 more seconds to the predicted time to drain and allowing the pump to drain fluid (at step 540) out of the tub 102 until the new PTTD is surpassed. Once the new PTTD has been surpassed, the pump is turned off (at step 552).

At step 542, when the predicted time to drain is not greater than the minimum threshold, the method continues by letting the pump drain until it reaches the predicted time to drain. Once the time has reached the predicted time to drain, step 544 indicates that the drain pump is turned off until it reaches the minimum drain time (at step 546). The method continues by re-operating the drain pump (at step 548) for an additional time period (in this embodiment, 15 more seconds at step 550) and then turning off the drain pump (at step 552).

Turning the pump off and then turning it on again before a final shut off are generally used steps to prevent the pump from running dry. Typically, 180 seconds is a minimum threshold in order to drain the water. Therefore, when the predicted time to drain has not reached the threshold of 180 seconds, the drain is turned off and then turned back on in order to drain any water that is drained from the load of items that may have dripped down into the washer tub 102 while the pump is turned off. In this manner, the time that the pump is on and running without water passing through it will be minimized. However, typically the minimum drain time is used in order to allow for sufficient time for water to drip off of the load being washed.

The method continues with proceeding to the next washer cycle (at step 554). Generally this cycle may be the spin cycle, however, this cycle may vary depending on the design and functionality of the washer machine unit.

The above description merely provides a disclosure of the some of the embodiments which may be implemented throughout the system. The above-provided description is not intended for purposes of limiting the claims. As such, this description is not limited only to the above described embodiments. Rather, one skilled in the art may conceive alternative embodiments which fall within the scope of the claims. 

1. A method for minimizing the period of time in which a drain pump is running in a vertical load washing machine comprising: determining an amount of fluid to fill a washing machine tub; measuring a time between a first level and a second level in said washing machine tub during draining; calculating a predicted time to drain based at least in part on said time and said amount to fill; and operating a drain pump for a period of time related to said predicted time to drain.
 2. The method according to claim 1, further comprising: deriving a minimum drain time; and operating said drain pump for at least said minimum drain time.
 3. The method according to claim 1, further comprising: setting minimal threshold for said predicted time to drain; and if predicted time to drain does not meet said threshold, operating said drain pump for said predicted time to drain and operating said drain pipe a second time for at least a portion of time until said threshold is meet.
 4. The method according to claim 1, wherein at said first level there is a first pressure switch and at said second level there is a second pressure switch.
 5. The method according to claim 4, further comprising checking for defects in said first and second pressure switches.
 6. The method according to claim 4, wherein said first pressure switch is configured to act as a safety switch in order to prevent flooding.
 7. The method according to claim 1, wherein determining said amount of fluid to fill said washing machine tub includes using a constant flow rate valve.
 8. The method according to claim 1, wherein the determining said amount of fluid to fill said washing machine tub included using a flow meter.
 9. The method according to claim 1, further comprising proceeding to the next cycle after said period of time has passed.
 10. The method according to claim 1, wherein calculating said predicted time is according to the formula A+B(TTT)−C(GTF) where A, B and C are constants and TTT is the time to trip and GTF is said measure of fluid.
 11. A method of operating a drain pump in order to minimize the length of time a drain pump is running to drain a washer tub comprising: determining a measure of fluid to fill said washer tub; initiating a timer; initiating a drain pump; recording a time to trip where said time to trip is the time it takes from the start of said drain pump to when a lower switch trips; and calculating a predicted time to drain based at least in part on said time to trip and said measure of fluid to fill said washer tub.
 12. The method according to claim 11, further comprising: turning off the drain pump if an upper level switch does not trip and said lower level switch does trip; and registering a fault of the upper level switch.
 13. The method according to claim 11, further comprising if said lower level switch has not tripped when said timer reaches a predetermined amount of time turning off said drain pump; and registering a lower switch fault.
 14. A system for an adaptive drain that calculates a predicted time for a washing machine to drain out fluid comprising: a washer tub having an upper level switch and a lower level switch; a drain pump configured to pump an amount of fluid out of said washer tub; and a controller adapted to regulate said drain pump to drain said washer tub for a period of time calculated to reflect a relationship between the time between the initiation of said drain pump, the time for said upper level switch to trip, and the time for said lower level switch to trip and the amount of fluid that said tub is holding.
 15. The system according to claim 14 wherein said upper level switch is a control switch that signals when said washer tub is in danger of overflowing.
 16. The system according to claim 14 wherein said upper level switch and lower level switch are pressure switches.
 17. The system according to claim 14 wherein said upper level switch and said lower level switch include fault detection.
 18. The system according to claim 17 wherein said upper level switch and said lower level switch reset after a fault is cleared.
 19. The system according to claim 14 wherein said controller is further configured to calculate said period of time to drain based on a predicted to drain according to the formula A+B(TTT)−C(GTF) where A, B and C are constants and TTT is the time to trip and GTF is said measure of fluid.
 20. The system according to claim 14 further comprising a constant flow rate value adapted to measure the amount of fluid used to fill said washer tub. 